


Fledgling Fear

by krysnel_nicavis



Category: Supernatural
Genre: Alternate Universe - Canon Divergence, Angst, Castiel's Angelic Grace (Supernatural), Denial, Gen, Mpreg, Post-Episode: s13e12 Various and Sundry Villains, Pre-Slash, angel grace pregnancy, pre-destiel
Language: English
Status: Completed
Published: 2020-06-09
Updated: 2020-06-09
Packaged: 2021-03-04 05:21:03
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,728
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24618247
Author URL: https://archiveofourown.org/users/krysnel_nicavis/pseuds/krysnel_nicavis
Summary: Two weeks after stabbing Lucifer outside Needham Asylum, Castiel throws up.This is not a good sign.But can something unforeseen be the key to helping Heaven instead of breaking it further? Even when it’s, technically (and unintentionally), Lucifer’s fault?
Relationships: Castiel & Dean Winchester
Comments: 4
Kudos: 27





	Fledgling Fear

Castiel knew stabbing Lucifer wouldn’t kill him. He was an Archangel after all, and Castiel was merely a Seraph. Higher than most in terms of raw power, but still lower than the Arch Host. It did make him feel better, though. There was also the added benefit of Lucifer’s weakened grace at least allowing Castiel to incapacitate him and get away.

He stumbled away from Needham Asylum, a hand pressed to his rib cage where Lucifer had managed to cut him when he’d dodged. As depowered as Lucifer was, he shouldn’t have been capable of inflicting this much damage on Castiel with this type of injury. He briefly recalled the time when Hannah’d had him tortured. Cut just enough to bleed a little and hurt a lot.

He winced at a sharp, cold, burning pain near the cut, coughing as blood filled his throat. He shouldn’t be this gravely injured. His vision blurred and he nearly lost his footing. He continued stumbling forward until another pain made his chest muscles contract. It was different from the last one, more abstract. Inside his grace. It felt… it felt almost as if a piece of it, a small piece, had cracked and broken off. It was tiny, almost a sliver, but the loss felt profound. Like there was something important he was forgetting. Honestly, the effect was more like a hiccup, only registering as pain due to the cut in his side.

He stumbled through the trees, into a clearing. The ground was swaying and everything was beginning to appear desaturated. The last thought that flitted through his mind was “this is odd” before the ground got closer and everything faded from view.

* * *

It took him a few days to reach the Bunker. He explained about Asmodeus and Lucifer and what he’d learned about the spell needed to open the Rift using Archangel grace. They made a plan to recreate the spell via the Demon Tablet and the soulless prophet, Donatello. They also attempted to capture Lucifer – failing miserably – during which they’d run into Ketch. The man irritated Castiel more than usual, and, when the former Men of Letters grunt suggested working together, Castiel had simply knocked him unconscious. He felt almost giddy when they’d locked him in the Impala’s trunk.

Now, almost two weeks after Lucifer had tried to consume his grace, Castiel was seated on a plane bound for Greece. They required fruit from the Tree of Life, located somewhere in Syria. The trip was unnerving him. Not because of how unbelievably slow it was compared to when he had his wings, nor because of how closely he was squeezed between two passengers. He’d been overcome by a sudden queasy feeling in his stomach not too long ago, and the only thing he could attribute the odd sensation to was the small bit of turbulence they’d experienced shortly before. It was disconcerting.

Less disconcerting was the little old woman seated next to him. She’d noticed his unease shortly after the turbulence and began speaking soothingly to him in a mix of stilted English and Greek, patting his hand in a comforting gesture. Her eyes lit up when he’d responded, also speaking Greek. She’d immediately begun telling him about her granddaughter’s wedding the previous week. Apparently she’d married and nice Greek boy and hoped to have a large number of children. He hoped their union was a blessed one.

The plane touched down in Athens, and the old woman wished him safe travels. He made his way to the ticket counter to figure out the next leg of his journey. Somewhere in the middle of the airport, the queasy feeling returned. His mouth was filled with saliva and his throat tightened, bile suddenly flooding his esophagus. His eyes jumped around, taking in the signage. He managed to locate the nearest washroom and make it to a toilet just as stomach acid and more bile was violently ejected from his stomach and, for the first time in his existence, he vomited.

The flight to Beirut was less unsettling and he continued his journey into Syria with two more upsets. He was becoming extremely wary, unable to account for the sudden illness his vessel was continuing to experience. It distracted him enough that, when the Djinn Queen bargained a treaty with him to spare the rest of her people (“A treaty of peace, sealed with a kiss so that we might be bonded in an uncontested alliance.”), he didn’t really stop to consider any possible underlying ramifications. Though, upon further examination, he was convinced it was more a technicality.

The vomiting continued, occurring more frequently after the next week. Thankfully, he was able to keep it hidden from Sam and Dean. They had enough to worry about at the moment.

The illness stopped nearly as suddenly as it started. And just as suddenly, he noticed other anomalies with his vessel. His pectorals were tender and he experienced cramping in his abdomen. The cramping only lasted a few days and was very minor. But his chest stayed tender. And he was becoming clumsy. Just enough for him to notice something was… _off._ But then they found out Gabriel was alive and had been held captive for years – _decades_ even, considering how time flows in Hell.

And then Gabriel was gone.

It was days later, when Castiel took a seat in the kitchen with Jack, that he first noticed the waistband of his pants dig a little into his abdomen in a way they never had before in the decade he’d inhabited this vessel. This issue became more prominent every day until he’s forced to mojo his waistline to accommodate the increasing girth. This was even more concerning than anything else that had happened, save the vomiting. But then, he’s told there are only ten other angels besides himself left and they’re struggling to keep Heaven powered, and there’s even more important things to worry about.

They managed to save Jack and Mary and some survivors from the Apocalypse World and strand Lucifer at the same time. Something they all knew wouldn’t last with how determined Michael was to come to their world. They’d come perilously close to losing Gabriel, for real this time. But, at the last moment, Sam managed to convince him _not_ to go after Micheal in a similar fashion to how Castiel had gone after Lucifer the previous year.

* * *

He idly watched the camaraderie around the Bunker’s main room a while before retreating to a less crowded area. He sensed Gabriel in the hallway behind him and turned to face him. Castiel was about to say how glad he was that his brother is still alive, but is words froze on his tongue. There was a peculiar look in the Archangel’s eyes. Eyes locked on Castiel’s midsection.

Castiel swallowed hard, a hand coming to rest on his somewhat distended abdomen. At this stage, his vessel merely appeared to have the beginning what many humans refer to as a gut. Gabriel opened his mouth to say something.

“Don’t.” Castiel’s hushed voice plead. His lips pressed into a thin line. He wondered if his internal distress was obvious. Gabriel looked at him with an unreadable expression. He simply nodded.

It had taken time for Castiel to piece it together. He just wanted to pretend for a little while longer. Just a little while. Until it’s completely undeniable.

* * *

It was late. Everyone in the Bunker was asleep. Well, _nearly_ everyone. Castiel wandered into the kitchen to find Dean seated at the table, an almost empty bowl of cereal in front of him.

“Hello, Dean,” he said.

“Hey, Cas.” Dean looked up, a welcoming grin on his face. He tilted his head, a small frown on his face. “You look different.”

Castiel started. It’d been busy in the Bunker lately, and… _it_ had only become glaringly obvious in the last couple days. He could see the moment when Dean realized what was different about him. He shifted uncomfortably under Dean’s steady gaze, adjusting his trench coat to hide the pronounced outward curve of his stomach, unable to meet the man’s eye.

Dean cleared his throat. “What, uh… what’s going on?” Castiel remained silent. “Cas?”

“It’s nothing,” Castiel replied, trying (and failing) to sound convincing.

Dean was unimpressed. “C’mon, Cas. Something’s obvi-“

**_“I said it’s nothing!”_ **

They both stilled. The air around them suddenly felt heavy in uncomfortable silence. Castiel chanced a glance at Dean. The man’s eyes stared wide, mouth open slightly. He’s startled. They both are. Castiel was’t even sure either of them were breathing at this point. Then Dean’s shoulders, tense and raised, dropped and he sighed.

“We both know that’s a load of crap.”

Castiel remained still. Frozen in time. He wanted to be frozen in time. To remain unmoving. As if, as long as he stayed still, time would too. And he could pretend a little longer. It only lasted seconds, this last ditch effort to cling to stasis. His head dropped forward and he exhaled a long, tired sigh. He braced his hands on the counter next to him and just stared down at it.

“Cas?” Dean’s voice low with worry.

Castiel wet his lips with his tongue. “Some…” He sighed deeply again. “Sometimes, when one Angel’s grace is exposed to a second Angel’s grace, a shard of the second Angel’s grace… splinters off. It – the shard, I mean – then… latches onto the first Angel’s grace, causing a shard of _that_ Angel’s grace to splinter off as well. The two shards then merge and… _incubate_ inside the first Angel’s grace until the blended piece is self-sufficient enough to survive on its own and breaks away.”

“… you’re talking about Angel baby making?” Dean sounded more than a little amused.

Castiel levelled a glare ate him. “Yes.”

The often infuriating man had the decency to look apologetic. He cleared his throat. “… so, you’re…” He gestured vaguely at Castiel’s stomach.

Castiel looked down, pressing a hand to the rounded bump. “It would appear so, yes.” He looked back up to see a flash of what almost looked like hurt in Dean’s eyes.

Dean looked away, clearing his throat. When he looked back, Castiel recognized the mask Dean frequently hid behind, the one intended to make him look impervious, had slid into place. “So, uh… who’s the lucky baby daddy?”

Castiel’s lips thinned, forehead creasing. He blinked rapidly. As much as he’d tried not to think of the condition he was currently in, he’d tried even harder to ignore who’d put him in it, however inadvertently. His voice was hushed, throat tight as he answered, “… Lucifer.”

“Lucif-” Dean looked as distraught as Castiel felt. The worried expression returned. They were silent again as he watched Dean gather his thoughts. “D-did he…?”

Castiel frowned, head tilted. “What?”

“Y’know.” Dean gestured indecipherably. “Did he…?” Castiel continued to frown, unable to decipher what the man was asking.

“I think he’s asking if there was force involved.” The two turned to see Gabriel leaning against the doorframe.

“Well, it took some force to use my Angel Blade,” Castiel replied matter-of-factly.

Gabriel stared blindly ahead. “Oh my dad…” He turned to Dean _”What_ have you been teaching him?”

* * *

The next morning, not wanting to be overheard, Sam, Dean, Castiel, and Gabriel gathered in the “Dean Cave”.

“If Angels are able to reproduce with each other, why is Heaven so interested in Jack to help rebuild their numbers?” Dean asked, taking a swig of his beer.

“The process must be triggered by an Archangel,” Castiel replied. “Since Jack is the Nephilim child of an Archangel, he may be strong enough to do it.”

“So, uh, why… why didn’t this happen during the whole thing with Amara?” Sam asked uncomfortably. “I mean, Lucifer was riding shotgun in you for nearly a year.”

Castiel shifted his stance. “The process is different when we’re in our true forms than when we’re in vessels.”

“You shared your vessel?” Gabriel asked, expression somewhere between a smirk and startled shock.

Castiel briefly raised an eyebrow at him, turning back to where the Winchester brothers were seated. “When in our true forms, the process is somewhat similar to when your species procreates, in that our graces become intertwined. When we were sharing a vessel, I was able to take precautions to prevent something like this from happening. Of course, it helped greatly that Lucifer never attempted to tamper with the barrier.”

“So, how did _this_ happen?” Dean asked, gesturing towards Castiel’s stomach with his beer.

“Lucifer was trying to convince me to allow him to consume some of my grace to boost his power. I refused. Repeatedly. He eventually managed to cut me… right before I stabbed him.” Castiel sighed at this, glancing around the room without really taking anything in. “I can only surmise that some of his grace must’ve gotten in through my cut. And since he _is_ an Archangel…”

“You got an angel-bun in the oven,” Dean supplied.

“Precisely.” He unconsciously settled a hand on his stomach. He could feel the new Angel’s presence beneath his palm. It was strong. Nearly as strong as his own grace class already and not even fully mature.

“So, uh, what are you going to do? When it’s… born? I guess?” Sam asked, unsure about the details.

“When the time comes for it to separate, it would not be wise for me to be anywhere near humans.”

“What? Why?” Dean asked, startled.

“Relax, Deano,” Gabriel cut in. “When mini-Cassie makes their debut, it’ll be in it’s true form. Which, as I recall, is not a good thing for your dainty little eyes to see. And, unlike Jack, this fledgling’s full angel. No vessel. It’s not wise for it to spring into existence on Earth.”

Dean heaved a sigh, running a hand over his face. “Well, shit.”

“If I remember correctly,” Castiel said, head tiled in thought. “It will also have a vast amount to knowledge when it separates.”

“Like memories?” Sam asked leaning forward, eagerness and curiosity shining in his eyes.

“Not exactly,” Gabriel replied. “It’ll be like being born with an encyclopedia in your head. All facts with no context. No experiences to adequately interpret what it _means_ , only that it _is.”_

Castiel considered for a moment. “In the beginning, fledglings had nest-mates. We were organized into small social groups. Within them, we began learning what the knowledge we had meant.“

“Me, Raphael, Micheal, and Lucifer are technically all the same age,” Gabriel said. “Sure, we became… aware… at different times, and we were created at different times, but we were all brought into consciousness on the same day.”

Again, Castiel placed a hand on his stomach, feeling the foreign grace beneath the surface. “It will need the kind of guidance only other Angels can provide. Despite certain misgivings, even I have to admit leaving it in Heaven is the best-”

“Wait, this is your kid we’re talking about,” Dean began arguing.

Castiel crossed his arms, frowning at the hunter he’d forged so strong a bond with those short years ago. “Dean.”

“C’mon, Cas. You can’t seriously be considering trusting _her_ with your-”

 _“Dean, please…”_ His shoulders were tense as he hugged himself. Dean stared at him, mouth opening and shutting like he wanted to continue. He watched as the hunter’s shoulders sagged, resignation and acceptance, and even a little understanding in his eyes.

This wasn’t an easy decision.

* * *

He still didn’t need to sleep, despite the fact that he was incubating a new Angel. But he was finding it more enjoyable to lounge and relax. More often than not, he could be found in Dean’s room, nestled on the memory foam mattress – which was definitely more comfortable than the other mattresses in the bunker – and surrounded in blankets and pillows, fully appearing to be asleep. Dean didn’t seem to mind, and it gave Castiel a place to take refuge away from all the new bodies around the bunker. He’d voluntarily forfeited the room designated as his in favour of giving one of the Apocalypse World refugees a place to sleep. If any of these new hunters noticed the change in his vessel, none had said anything, and he’d prefer to keep it that way.

Something in their interactions – his and Dean’s – had begun to shift. It began one night when Castiel had been relaxing in Dean’s bed. He was dressed in a t-shirt and boxers since he’d begrudgingly agreed it was more comfortable than trying to relax in his usual suit and trenchcoat. He’d sensed Dean enter the room and ready himself for bed, so he’d pushed himself up, intending to give the man his bed back.

“Nah, just stay there. You need the rest,” Dean had grumbled tiredly, slipping into the bed next to him.

“I don’t require sleep, Dean. You do,” he’d countered.

Dean tugged on his arm until he’d resumed lying down. “S’okay. Better for you to relax anyway.” He’d immediately fallen asleep and that was the end of that. At some point, in his sleep, Dean had curled an arm around his midsection, head on Castiel’s shoulder, warm, even breathing against the skin of his collar. Castiel relaxed, allowing his consciousness to drift in the closest imitation of sleep he was capable of.

Several times over the following weeks his consciousness drifted back into focus to the sound of Dean speaking. He was confused the first time this happened. Dean was talking about not letting “those dicks in Heaven push you around”. He soon realized Dean wasn’t talking to him, he was talking to his stomach. It was a common thing Castiel had observed in humans, parents speaking directly to developing foetuses. It helped the foetus’ development and acclimated it to the sounds of the voices it would most commonly hear. It also helped parents form emotional attachments to it. He eventually tried to talk do Dean about this.

“You know, the fledgling isn’t actually inside me. Not in the traditional sense,” he’d explained. Or tried to. “Yes, it’s grace is essentially centred in my abdomen, but it’s not physically in there so there are no foetal movements.”

Despite this, and him explaining that the “baby bump” was just a physical manifestation to visually reflect his incubation of a fledgling Angel, Dean insisted on treating it like there was an actual baby growing inside. He continued to hold one-sided conversations with it, all while insisting he wasn’t forming any sort of attachment to it. “Why bother if it’s just going to stay in Heaven.” Castiel was also convinced Dean’s reluctance to form an attachment was because it was half Lucifer’s. Regardless of how Jack was turning out, it was still an obvious sticking point with Dean.

They were lying side by side on Dean’s bed. The fledgling was expected to separate in less than a week and they were enjoying a moment of relaxation together. Dean’s hand was gently rubbing Castiel’s now _very_ round stomach. The man couldn’t sense the grace beneath his palm. Other than the shape of Castiel’s body, there was no other indication for weaker human senses that said anything was even there. But Castiel could sense the fledgling. It’s grace was so much stronger now that it had been. So much so that his own grace was beginning to tingle around it. And when Dean’s hand moved across his skin, fledgling grace followed. It had been for the last week, already becoming aware of what was around it. Given how adamant Dean was about not forming attachments, Castiel had elected not to tell him. Because he was right: it was going to stay in Heaven.

Castiel covered Dean’s hand with his own, feeling the fledgling’s grace through the man’s hand and the flesh of his vessel. He idly wondered if Dean sensed anything when he did this. “I know you don’t like this.”

“Cas…”

“And I get it. I don’t exactly like what’s happening either.” He reordered his thoughts. “With Lucifer… and Heaven… a-and _Naomi_ … I just…” He swallowed a lump forming in his throat, his eyes stinging.

Dean wrapped around him more securely. “Hey, shh. It’s okay, Cas.”

Castiel leaned into him. “It’s so _strong,_ Dean.” He pressed their hands more firmly to his skin. “So much stronger than I am. I just _know_ it can help…” His breath hitched. “It can fix what I broke…”

Dean’s hand lifted from his stomach and brushed tears from his face. His warm lips pressed gently to Castiel’s temple, his eyes, his nose… He turned Cas’ head and pressed a kiss to his lips. Gentle and sympathetic and _understanding._ There was a promise in that kiss.

They lay next to each other, held each other close. And they pretended.

They pretended there was nothing to get attached to.

* * *

One fear Castiel had with regards to leaving the fledgling to be nurtured in Heaven was that it would end up being trained the way he had been. That it would end up becoming a mindless soldier like so many of his brothers and sisters and himself. Being reset whenever it showed a trace of individuality or free will. Naomi’s promises that that wouldn’t happen felt hollow in his chest. Heaven was going to be rebuilt from the ground up, so to speak. Their ranks were going to be replenished until everything could run business as usual. Despite this being a reason for Castiel to want to take his fledgling and run, it was also the biggest reason for it to stay.

As Castiel had predicted, it was an Archangel class. It had, or would develop, the power to begin repopulating Heaven’s Host. Naomi insisted on Heaven’s doors being kept shut for the time being. Until the repopulation effort had picked up more steam. With everything going on back on Earth, Castiel couldn’t justify staying in Heaven to himself. It was only Naomi’s assurances that “business as usual” didn’t mean “as things were done under Michael”.

“I think it’s time we returned to our original purpose, don’t you Castiel?” Cas wasn’t completely sure what that meant any more, but he decided to take a “leap of faith”.

He returned to the bunker alone.

If he lay in bed that night in the arms of his favourite Winchester and cried… well, he was once the angel of humanity and tears…

\- 30 -

**Author's Note:**

> So after 2 years, I stumbled across a prompt note I’d left on my phone saying “2 weeks after stabbing Lucifer (13.12), Castiel throws up”, followed by 2 dialogue-only scenes explaining angel pregnancies to the Winchesters.
> 
> My first thought was “when did Cas stab Lucifer in season 13?”. After Google reminded me, my second thought was: “This should be interesting.”
> 
> Hope you enjoyed.
> 
>  **Edit Note:** Castiel’s angelic pregnancy lasted 99 days (14 weeks + 1 day).


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